Method for preventing the shrinkage of woolen or wool blend fabrics

ABSTRACT

Method for preventing the shrinkage of woolen or wool blend fabrics during water washing treatment, comprising the initial impregnation of the fabric of interest with a reducing product (compound A) and after suitable mechanical and drying treatment, the subsequent contact of the resulting fabric with a blend of products comprising at least one compound of each of the following groups: vinylic and acrylic resins, ethylene vinyl acetates, blocked or non-blocked isocyanates, blocked or non-blocked in water and solvents polyisocyanates (compound B); blocked or non-blocked in water and solvents polyisocyanates (compound C); silicon emulsions, macro-emulsions, cationic fabric conditioners (compound D).

The present invention relates to a method for preventing the shrinkageof woolen or wool blend fabrics during water washing operations. Thismethod substantially comprises a treatment of the fabric of interestwith suitable blends of chemical products, which, in turn, form anintegral part of the invention.

Woolen or wool blend articles are normally dry-cleaned to eliminategreasy dirt, but a perfect cleaning is not obtained with respect tocommon dust, unfortunately to the detriment of people suffering fromallergies; furthermore, exhalations of the products used in dry cleaningcause water and atmosphere pollution (law of Dec. 28, 1993 nr. 549modified by the law of Jun. 11, 1996 nr. 315). In return, water washingcertainly offers greater hygiene but does not guarantee that the woolenor wool blend article does not modify its structure.

The Applicant has now found, and this is the object of the presentinvention, that it is possible to give dimensional stability to woolenor wool blend fabrics by means of treatment with suitable combinationsof chemical products, which also form an object of the presentinvention. Articles manufactured with the fabric thus treated can besubjected to water washing at a temperature of about 30/40° C. inspecific laundry machines or household washing machines, preventingmacroscopic felting.

Chemical processes are known for conferring unshrinkability to woolenarticles, but they are only a few of these which normally refer toknitted or combed fabrics. Chemical treatment used for anti-feltingprocesses are substantially the following:

-   -   degradation processes (oxidation, in particular), which are        effected using chlorine or organic derivatives of chlorine in an        aqueous medium: this treatment causes more or less damage to the        woolen fibers, such as weight loss, a reduction in mechanical        resistance, a decrease in the elasticity, all unfavorable        changes on the final result of the fabric (normally called        “feel”);    -   additional processes, by applying polymers such as polyamines,        polyacrylates, reactive polyolefins;    -   processes deriving from the combination of those mentioned        above.

The method set up by the applicant and which, as already mentioned,constitutes an object of the present invention, makes use of a suitablecombination of known techniques and, at the same time, applies thesetechniques by using a particular combination of chemical products whichconfer unshrinkability to woolen fabrics and do not produce any of theundesired side effects which, according to the known art, derive fromthe use of the above-mentioned chemical products on the woolen fabrics.

An object of the present invention therefore relates to a method forpreventing the shrinkage of woolen or wool blend fabrics during waterwashing treatment, consisting of subjecting the fabric of interest to acombined action of a reducing product and a further three products to beadded in a subsequent phase, and sending the fabric thus treated tosuitable squeezing and finishing operations.

This treatment, in addition to preventing the macroscopic felting of thearticle during washing in household washing machines, also prevents thefinal deterioration of the fabric, which is inevitable in the treatmentof the known art, and, finally, also allows the heaviest woolenarticles, such as jackets, trousers and overcoats, to be treated.

In particular, the present invention relates to a method for preventingthe shrinkage of woolen and wool blend fabrics during water washingoperations which includes the initial impregnation of the fabric ofinterest with a reducing compound and, after suitable mechanical anddrying treatment, subjecting the resulting fabric to the action of ablend of products comprising at least one compound for each of thefollowing groups:

-   -   vinylic and acrylic resins, ethylene vinyl acetates, blocked or        non-blocked isocyanates, blocked or non-blocked in water and        solvents polyisocyanates;    -   blocked or non-blocked in water and solvents polyisocyanates;    -   silicon emulsions, silicon micro-emulsions, macro-emulsions,        cationic fabric conditioners.

The fabric thus obtained is finally mechanically treated and dried.

The reducing compound (compound A) is selected from sulfites,di-sulfites and formiates; a single compound can be used, or a mix oftwo or more substances at various concentrations and percentages.

With respect to the compounds adopted for carrying out the second phaseof the treatment, these are used, according to different percentages, ina mix whose combination is, in turn, an object of the present invention.This combination, as mentioned, uses at least one compound for each ofthe above-mentioned groups which, once again, are:

-   -   Compound B: vinylic and acrylic resins, ethylene vinyl acetates,        blocked or non-blocked isocyanates, blocked or non-blocked in        water and solvents polyisocyanates;    -   Compound C: blocked or non-blocked in water and solvents        polyisocyanates;    -   Compound D: silicon emulsions, silicon micro-emulsions,        macro-emulsions, cationic fabric conditioners.

The above products, as such or in blends of suitable percentages, areput in contact with the fabric to be treated in amounts of up to 50% byweight with respect to the total weight of the fabric. The treatment iseffected on the fabric, before manufacturing the items of clothing, andis substantially inserted in the finishing steps of the fabric.

The method according to the present invention comprises the treatment offabric in several steps:

-   -   the fabric is impregnated with compound A at a temperature        ranging from 0° C. to    -   the fabric thus treated is subjected to squeezing or        centrifugation, then dried;    -   the fabric thus obtained is impregnated with compound BCD at a        temperature ranging from 0° C. to 100° C. When the BCD compound        is a blend, the products are present in various percentage        ratios, whose value is selected by experts in the field on the        basis of the results to be achieved;    -   finally, the fabric is squeezed and/or centrifuged and dried.

The following example will add further details to and contribute toproviding a better illustration of the method according to the presentinvention, without, however, limiting its scope.

EXAMPLE

1^(st) Step

The treatment or pad bath is heated to a temperature ranging from about20° C. to 100° C. (FIG. 1) in the presence of one or more productsselected from the reducing compounds, care being taken not to createstress in the warp and ensuring that the bath penetrates inside thefabric and not only on the surface, consequently exerting a pressure of40-50 bar by squeezing or basket centrifugation.

The fabric is dried at a temperature of 110-120° C. over the dryingstenter (drying machine).

The fabric is fed to the stenter machine—care being taken not to exceeda height of 5/10 cm in the stenter machine above the height of thefinished fabric, as this can create too much stress—until the fabricreaches its regular warp tension, subsequently recovering its initialconditions in dimensional terms (before step 1 of the treatment).

The fabric leaves the stenter machine dried.

2^(st) Step

The fabric is inserted into an intermitted barrel decatizing machinewith “molleton” or “glazing finish” supplying vapour for 4 minutes,continuously, with no pump, care being taken that there is no locking orstress in the warp or in a KD machine.

It is recommended to mark two signals at about 1 meter from theheadboard in the warp direction. The reciprocal distance between thesignals should be 100 cm, to control the operation and prevent lockingor stress. This control should be effected for all productions, in orderto discover working methods which can generate undesired stress andconsequently make the desired corrections.

The fabric thus treated can then be submitted to the necessary finishingoperations.

It should therefore be dried again, with the usual precautions for weavestress and warp overfed to the maximum, the distances of the two signalsbeing constantly restored to 100 cm, as described above.

3^(rd) Step

The pad bath is prepared again for the second combination of products,consisting of one or more products selected from B, C and D; the dryingphase in the stenter machine is then effected, care being taken toobserve all methods and precautions already mentioned in Step 1 and 2.The fabric is vaporized and rolled up.

For the treatment in question, the tank (FIG. 1) should be equipped witha minimum of three and a maximum of five cylinders, situated,respectively: nr. 1 immersed in the bath and nr. 2 out of the bath; nr.3 immersed in the bath and nr. 2 out of the bath. The bath temperatureranges from 20 to 100° C.

The contact of the fabric with the cylinders has a sponge effect, theliquid penetrates inside the depth of the fabric and is definitely driedwith various types of equipment.

1. A method for preventing the shrinkage of woolen or wool blend fabricsduring water washing treatment, comprising the initial impregnation ofthe fabric of interest with a reducing product (compound A) and, aftersuitable mechanical and drying treatment, the subsequent contact of theresulting fabric with a blend of products comprising at least onecompound of each of the following groups: vinylic and acrylic resins,ethylene vinyl acetates, blocked or non-blocked isocyanates, blocked ornon-blocked in water and solvents polyisocyanates (compound B); blockedor non-blocked in water and solvents polyisocyanates (compound C);silicon emulsions, macro-emulsions, cationic fabric conditioners(compound D).
 2. The method for preventing the shrinkage of woolen orwool blend fabrics according to the previous claim, wherein the reducingproduct (A) consists of one or more compounds selected from sulfites,di-sulfites and formiates.
 3. The method for preventing the shrinkage ofwoolen or wool blend fabrics according to claim 1, wherein the productsselected from A, B, C and D, as single compounds or as blends of morecompounds, are put in contact with the fabric to be treated in a totalamount of up to 50% by weight with respect to the total weight of thefabric.
 4. The method for preventing the shrinkage of woolen or woolblend fabrics according to claim 1, wherein the two treatments with theabove-mentioned products are carried out at temperatures ranging from 20to 100° C.
 5. Blend of compounds to be used in a treatment forpreventing the shrinkage of woolen or wool blend fabrics during waterwashing operations, comprising at least one compound of each of thefollowing groups: vinylic and acrylic resins, ethylene vinyl acetates,blocked or non-blocked isocyanates, blocked or non-blocked in water andsolvents polyisocyanates; blocked or non-blocked in water and solventspolyisocyanates; silicon emulsions, macro-emulsions, cationic fabricconditioners.